Stirling engine comprising metal foam regenerator

Abstract

A Stirling engine comprising:a crank case (1) with a crank shaft (2) arranged therein,a displacer cylinder (3) with a reciprocatingly arranged displacer piston (4) therein, said displacer piston (4) being connected to said crank shaft (2) via a connecting rod (5) extending through a first end of said displacer cylinder (3), and wherein the displacer cylinder (3) defines a hot chamber (6) and a cool chamber (7) separated by the displacer piston (4),a working cylinder (8) defining a working cylinder chamber (11) with a reciprocatingly arranged working piston (9) therein, said working piston (9) being connected to said crank shaft (2) via a connecting rod (10) extending through a first end of the working cylinder (8),a heater device (14), arranged at a second end of said displacer cylinder (3) opposite to said first end and configured to heat a working gas which is present in the hot chamber (6) of the displacer cylinder (3) and in fluid communication with the working cylinder chamber (11) through a working gas channel which comprisesa first heat exchanger (16) extending from a head (19) of the displacer cylinder (3) into the heater device (14), anda second heat exchanger (17) formed by a regenerator arranged outside the heater device (14). The regenerator (17) comprises a regenerator element (17) formed by metal foam that has an open porosity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is the U.S. National Phase under 35. U.S.C. § 371 of International Application PCT / SE2018 / 051352, filed Dec. 20, 2018, which claims priority to Swedish Patent Application No. 1850003-3, filed Jan. 2, 2018. The disclosures of the above-described applications are hereby incorporated by reference in their entirety.TECHNICAL FIELD[0002]The present invention relates to a Stirling engine comprising:[0003]a crank case with a crank shaft arranged therein,[0004]a displacer cylinder with a reciprocatingly arranged displacer piston therein, said displacer piston being connected to said crank shaft via a connecting rod extending through a first end of said displacer cylinder, and wherein the displacer cylinder defines a hot chamber and a cool chamber separated by the displacer piston,[0005]a working cylinder defining a working cylinder chamber with a reciprocatingly arranged working piston therein, said working piston being connected...

AI Technical Summary

Benefits of technology

The present invention is about a new design of a regenerator for a Stirling engine. The regenerator should be efficient at exchanging heat with the working gas and should have high thermal stability and fatigue strength. It should be rigid so as to not get compressed under the pressure that it may be subjected to. The regenerator should also have a low pressure drop over it. There is a need for a regenerator that is easy to install and exchange, and metal foam has been found to be a suitable material for this purpose. The metal foam has high heat exchanging capacity and allows for rapid heat exchange without getting too much heat. The regenerator element should also have lower hydraulic and matrix porosity towards the higher temperature end. Overall, the invention aims to improve the performance of the regenerator in a Stirling engine.

Problems solved by technology

Accordingly it is a challenge to design a regenerator that fulfils all these requirements.

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